Stylet

ABSTRACT

A stylet providing preselected alignment of a hollow outer needle, an inner stylet and a boss and comprising a shaft having an angular portion at one end in predetermined alignment with a bevelled point at the other end, a handle having an inferior hub portion and having a key-slotted central passage communicating with an axially aligned passage in said hub portion, said hub passage adapted to permit the shaft of said needle to be inserted therethrough, said handle passage adapted to nonrotatably retain said angular portion of said needle in said key-slot, and a boss located on the exterior of said hub portion, said boss in predetermined alignment with said key-slot such that the stylet can be aligned with its bevelled end in registry with the bevelled end of the outer hollow needle. The angular portion of the stylet may be positioned in the key slot so as to provide a predetermined shaft length between the hub and the bevelled end thereof, and the angular portion may be bonded in such position.

United States Patent Primary ExaminerJoseph S. Reich Attorney-Kane, Dalsimer, Kane, Sullivan and Kurucz ABSTRACT: A stylet providing preselected alignment of a hollow outer needle, an inner stylet and a boss and comprising a shaft having an angular portion at one end in predetermined alignment with a bevelled point at the other end, a handle having an inferior hub portion and having a key-slotted central passage communicating with an axially aligned passage in said hub portion, said hub passage adapted to permit the shaft of said needle to be inserted therethrough, said handle passage adapted to nonrotatably retain said angular portion of said needle in said key-slot, and a boss located on the exterior of said hub portion, said boss in predetermined alignment with said key-slot such that the stylet can be aligned with its bevelled end in registry with the bevelled end of the outer hollow needle. The angular portion of the stylet may be positioned in the key slot so as to provide a predetermined shaft length between the hub and the bevelled end thereof, and the angular portion may be bonded in such position.

PATENTEDJUNZZIQTI 3585.986

\ INVENTOR #461 27 E Mfr/g;

ggyzwiLs amfw ATTO R N 5Y5 STYLET BACKGROUND OF THE INVENTION This invention relates to an improved stylet having a bevelled point capable of exact alignment with the bevelled point of a spinal anesthesia or other technique type needle. In particular, it relates to improved stylet having a bevelled point in exact alignment with a boss on the handle of said stylet.

When elongated hollow needles are inserted into the body, it is often necessary to employ an interiorly mounted stylet in order to strengthen such needle during insertion. The stylet also prevents the hollow point of the needle from becoming plugged with body debris. For this purpose, it is critical that the bevelled portion of the stylet needle be exactly aligned with the bevelled portion of the cannula of the outer needle. Should the stylet point be misaligned with the outer needle point, then during insertion of the stylet-strengthened outer needle into the body, undue tissue damage is observed. Further, there is a danger that the hollow point of the outer needle may break off during insertion.

Various methods have been employed in order to maintain the points of the cannula and stylet needle in proper registry. In US. Pat. No. 3,175,554 an outer needle having a notch in the fitting of the outer needle is described. The notch is aligned with the bevelled point of the outer needle. A stylet is provided having a boss in alignment with the bevelled point of the stylet needle. As is illustrated in FIG. 3 of the aforesaid patent, registry is maintained by seating the boss of the stylet in the notch of the fitting of the outer needle.

Many problems have arisen in attempting to fabricate stylets suitable for long needles. The stylets all must exhibit exact external length. The bevelled point of the stylet must be in exact alignment with the boss on the stylet handle. Many conventional methods for aligning the stylet point with a boss on the handle and for insuring a uniform stylet bore length have proven impractical, unwieldy and, more important, incapable of being adapted for mass production of such aligned stylets.

Accordingly, there exists a need for a stylet capable of being readily fabricated having a uniform external length and a boss and bevelled point in exact alignment.

SUMMARY OF THE INVENTION A stylet is provided having a handle portion capable of nonrotatably positioning an angular end portion of a stylet needle, such that a boss on the upper hub of the stylet handle is exactly aligned with the lower bevelled point of the stylet. The angular stylet needle end portion is capable of longitudinal movement within the handle prior to joinder with said handle. ln assembly, an upper end of a stylet needle is bent in predetermined alignment with a bevelled point at the lower end. Thereafter, the stylet bent portion is introduced into a key-slot in the stylet handle and positioned such that a predetermined external stylet length is achieved. Finally, the bent portion of the needle is fixedly joined to the handle within the key-slot.

BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings:

FIG. 1 is a front elevational view of the stylet of the invention;

FIG. 2 is a vertical, partly fragmentary, sectional view of the stylet taken along line 2-2 of FIG. 1;

FIG. 3 is an enlarged horizontal sectional view of the stylet taken along line 3-3 of FIG. 2;

FIG. 4 is a vertical sectional view, partly fragmentary, of a stylet in seating alignment with an outer needle;

FIG. 5 is a horizontal sectional view of the stylet in combination with an outer needle taken along line 5-5 of FIG. 4; and

FIG. 6 is an exploded sectional view illustrating the individual components of the stylet and their relationship to the outer needle.

DESCRIPTION OF THE PREFERRED EMBODIMENT As illustrated, particularly in FIGS. 1-6, the stylet 10 has a bevelled point at one end 12 and a bent portion 14 at the other end. Although a stylet needle having a bend is illustrated, other angled bends may be employed, as well as double reversed bends. The direction of the bend is predetermined with respect to the plane of the bevelled end point. As illustrated, a workable stylet has a 90 bend directly aligned with the bevelled point thereof such that a plane may be passed through the axis of the entire stylet, including the bent terminal end.

A stylet handle 16 is provided having an inferior hub portion 18. An annular passage 20 is provided from the top of the handle to the hub portion. As illustrated in FIG. 3, the passage is key-slotted along the entire length of the handle passage so as to accommodate the bent portion of the stylet. The stylet is capable of longitudinal movement within the key-slot, but is nonrotatably positioned within the central passage. Hub I8 has an annular passage 22 axially aligned with the handle passage. The hub passage is of a diameter sufficient to snugly fit about the shaft of the stylet. As illustrated, the key-slot is a channel formed by a pair of parallel flanges 32, 32 positioned along the walls of the central passage.

A boss 24 is positioned on the hub of the stylet handle in a predetermined alignment with the key-slot. A workable alignment is illustrated in the drawings, wherein the boss is directly aligned with the axis of the key-slot. As illustrated in FIG. 6, when the stylet is inserted through the handle and hub and the bent portion of the stylet is introduced into the key-slot, the bevelled point is directly aligned with the boss on the hub.

It is understood, of course, that both the alignment of the bent portion of the stylet and the bevelled point of the needle may be varied in order to produce a different predetermined alignment between the boss and bevelled end upon assembly of the stylet. Similarly, the alignment between both the boss and key-slot may be varied during fabrication of the handle in a predetermined manner, such that upon insertion of the bent stylet, a predetermined alignment is obtained between the boss and bevelled portion of the stylet point.

The stylet is particularly useful in combination with an outer needle having a notched fitting and a bevelled pointed end wherein the notch and the bevelled point are in direct alignment. As illustrated in FIGS. 4 through 6, when the stylet is in troduced into the fitting 26 of the outer needle, boss 24 is locked in notch 28 with the result that the bevelled end of the outer needle and the bevelled point of the stylet are in exact registry. It will be seen that as long as the predetermined alignment between the notch of the outer needle and its bevelled end and the predetermined alignment between the boss on the stylet hub and the bevelled end of the stylet needle are identical, then after mating the stylet with the outer needle, the registry of the bevelled pointed ends will always be maintained.

It is an important feature of the invention that the external length 30 of the stylet needle projecting beyond the hub portion of the stylet handle, is adjusted merely by sliding the bent portion of the needle to a selected point within the key-slot and, thereafter, joining the bent portion to the handle employing conventional techniques.

A method is provided for fabricating the improved stylets whereby a uniform external length is obtained for each stylet, while maintaining a predetermined alignment between a boss on the handle and the bevelled point at the needle end.

Stylet handles are formed employing conventional processes; for example, extruding and/or injection molding processes. In a preferred embodiment, the key-slot in the handle is directly aligned with the boss on the hub below. Stylet wire is cut into approximately equal lengths. The individual lengths of stylet wire need not be identical. Each length should be at least long enough to provide the required external length, and sufficient additional wire to form an internal bent portion which can be mounted in the lowermost portion of the key-slot of the stylet handle. The maximum length of the wire should be no greater than that length needed to produce the required external length and an internal portion to be positioned in the uppermost portion of the slot in the handle.

Within these limits, any length of stylet wire may be employed. Thereafter, the wires may be placed adjacent one another and bent to the preselected angle at one end. Next, conventional grinding techniques may be employed to bevel the opposite ends of the wires at the preselected alignment angle with the upper bend. If desired, this operation could be reversed and the wires could be bevelled initially and, thereafter, bent to the required angle at the required alignment.

Next, the lengths of wire are individually inserted into the stylet handle by mechanical or manual means and a preselected external length is exposed. In order to achieve this desired length, the bent portion of the wire is longitudinally manipulated within the key-slot of the handle. A uniform external length is achieved for all stylets in this manner, although the individual lengths of the stylet wires may have varied initially. Similarly, the bevelled tips of all the stylet wires are uniformly aligned with the bosses on the stylet handles in the same manner. When the predetermined external length is attained, the bent portion of the stylet wire is joined to the slotted stylet handle. Conventional adhesives may be applied for this purpose. Epoxy adhesives have been found especially suitable.

It will thus be seen that an improved stylet is provided which can be fabricated to meet a variety of preselected conditions involving preselected length, alignment with an outer special technique type needle, and the likev A simplified method is provided for fabricating a stylet having a boss and a bevelled needle end aligned in any preselected manner. It will be understood, of course, that other modifications may be made in the illustrated invention within the purview of one skilled in the art.

lclaim:

l. A stylet comprising in combination: a stylet having a shaft having an angular portion at one end extending in predetermined alignment with a bevelled point at the other end, a handle having an inferior hub portion and having a key-slotted central passage communicating with an axially aligned passage in said hub portion, said hub passage adapted to permit the shaft of said stylet to be inserted therethrough, said handle passage adapted to nonrotatably retain said angular portion of said stylet in said key-slot, and a boss located on the exterior of said hub, said boss in predetermined alignment with said key-slot, whereby said boss is in selected alignment with the bevelled point of said stylet when said needle is mounted in said handle.

2. A stylet comprising in combination: a stylet having a shaft having a substantially bent portion at one end said key-slot, said slot being aligned with a bevelled point at the other end, a handle having an inferior hub portion and having a key-slotted central passage communicating with an axially aligned passage in said hub portion, said hub passage adapted to permit the bore of said stylet to be inserted therethrough, said handle passage adapted to nonrotatably retain said bent portion of said stylet in the channel formed by a pair of parallel flanges positioned along the interior wall of the central passage, and a boss located on the exterior of said hub, said'boss being in direct alignment with the channel formed between said flanges, whereby said boss is in direct alignment with the bevelled end point of the stylet.

3. A method for fabricating and assembling a stylet having a boss in predetermined alignment with the bevelled end of a stylet needle comprising:

a. forming a stylet handle having an inferior hub portion,

forming said handle with a key-slotted central passage communicating with an axiall aligned gassage in said hub portion, forming said han le with a oss located on the exterior of said hub in a predetermined alignment with said key-slot,

b. forming a stylet with a shaft having an angular portion extending at one end and a bevelled point in a predetermined alignment with said angular portion at the other end,

c. inserting the stylet, bevelled end first, through the central passage of said stylet handle and introducing said angular portion of said stylet into said key-slot such that a preselected external length is obtained, and

d. bonding said angular portion within said slot within said handle.

4. In an outer needle in combination with an inner stylet, said needle and stylet having bevelled pointed ends in registry, said stylet having a handle attached to the other end thereof and being seated in a fitting attached to the other end of said needle, said stylet handle having a boss on the exterior thereof, said fitting having a notch in the interior thereof adapted to be engaged by said boss, the improvement wherein the bevelled point of the stylet is aligned with the handle boss and said stylet has a shaft having an angular portion extending from said other end thereof in predetermined alignment with said bevelled pointed end, said handle having an inferior hub portion and having a key-slotted central passage communicating with an axially aligned passage being in said hub portion, said hub passage adapted to permit the shaft of said stylet to be inserted therethrough, said handle passage being adapted to nonrotatably retain said angular portion of said stylet in said key-slot, said boss being positioned in predetermined alignment with said key-slot, whereby said boss is in alignment with the bevelled point of said needle and said stylet when said stylet is mounted in said handle. 

1. A stylet comprising in combination: a stylet having a shaft having an angular portion at one end extending in predetermined alignment with a bevelled point at the otHer end, a handle having an inferior hub portion and having a key-slotted central passage communicating with an axially aligned passage in said hub portion, said hub passage adapted to permit the shaft of said stylet to be inserted therethrough, said handle passage adapted to nonrotatably retain said angular portion of said stylet in said key-slot, and a boss located on the exterior of said hub, said boss in predetermined alignment with said key-slot, whereby said boss is in selected alignment with the bevelled point of said stylet when said needle is mounted in said handle.
 2. A stylet comprising in combination: a stylet having a shaft having a substantially bent portion at one end said key-slot, said slot being aligned with a bevelled point at the other end, a handle having an inferior hub portion and having a key-slotted central passage communicating with an axially aligned passage in said hub portion, said hub passage adapted to permit the bore of said stylet to be inserted therethrough, said handle passage adapted to nonrotatably retain said bent portion of said stylet in the channel formed by a pair of parallel flanges positioned along the interior wall of the central passage, and a boss located on the exterior of said hub, said boss being in direct alignment with the channel formed between said flanges, whereby said boss is in direct alignment with the bevelled end point of the stylet.
 3. A method for fabricating and assembling a stylet having a boss in predetermined alignment with the bevelled end of a stylet needle comprising: a. forming a stylet handle having an inferior hub portion, forming said handle with a key-slotted central passage communicating with an axially aligned passage in said hub portion, forming said handle with a boss located on the exterior of said hub in a predetermined alignment with said key-slot, b. forming a stylet with a shaft having an angular portion extending at one end and a bevelled point in a predetermined alignment with said angular portion at the other end, c. inserting the stylet, bevelled end first, through the central passage of said stylet handle and introducing said angular portion of said stylet into said key-slot such that a preselected external length is obtained, and d. bonding said angular portion within said slot within said handle.
 4. In an outer needle in combination with an inner stylet, said needle and stylet having bevelled pointed ends in registry, said stylet having a handle attached to the other end thereof and being seated in a fitting attached to the other end of said needle, said stylet handle having a boss on the exterior thereof, said fitting having a notch in the interior thereof adapted to be engaged by said boss, the improvement wherein the bevelled point of the stylet is aligned with the handle boss and said stylet has a shaft having an angular portion extending from said other end thereof in predetermined alignment with said bevelled pointed end, said handle having an inferior hub portion and having a key-slotted central passage communicating with an axially aligned passage being in said hub portion, said hub passage adapted to permit the shaft of said stylet to be inserted therethrough, said handle passage being adapted to nonrotatably retain said angular portion of said stylet in said key-slot, said boss being positioned in predetermined alignment with said key-slot, whereby said boss is in alignment with the bevelled point of said needle and said stylet when said stylet is mounted in said handle. 